Communication devices, such as vehicular radios, often include illuminated controls for various radio functions such as volume adjustment, channel change and the like. Designing rotary illuminated controls for the vehicular radio environment is often challenging, as the rotary control can be difficult to fit within a limited form factor of the radio's control panel.
In a dark vehicular environment, a control knob may be insufficiently lit or not lit at all, thus making the control difficult to locate. illumination resolution is typically limited by the number of light sources and thus a light indicator may only show up as a single dot. The use of additional light sources may not be feasible for applications restricted by size and cost. Also, the use of numerous light sources further burdens electrical circuitry and software control.
Additionally, state or level information pertaining to the control, for example volume level, is typically displayed on a separate display which is located elsewhere on the control panel away from the volume control knob. For vehicular applications, drivers typically have to take a quick glance at the separate display to identify the current control state while driving, which can be distracting. Using independent displays in such a manner is also extremely costly.
Accordingly, there is a need for an improved approach to lighting a control for a communication device.